Possible problems with sending comment notifications to a new user?

(Bug, Investigate , Priority: Critical, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
Summary: Needs looking into: I don't have any reason to believe anything is broken in this area, but this is worrying.
From Eric:
A couple weeks ago, I made a test user, and went to ``Actions > Advanced..." and selected 'True" for "Send me a Message whenever someone comments in this Space".
With another account, I just made a couple of Readable comments on Readable items (the test user can see them no problem) - but the Recent Messages page for that user remains empty.